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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * ADS7846 based touchscreen and sensor driver
4 *
5 * Copyright (c) 2005 David Brownell
6 * Copyright (c) 2006 Nokia Corporation
7 * Various changes: Imre Deak <imre.deak@nokia.com>
8 *
9 * Using code from:
10 * - corgi_ts.c
11 * Copyright (C) 2004-2005 Richard Purdie
12 * - omap_ts.[hc], ads7846.h, ts_osk.c
13 * Copyright (C) 2002 MontaVista Software
14 * Copyright (C) 2004 Texas Instruments
15 * Copyright (C) 2005 Dirk Behme
16 */
17#include <linux/types.h>
18#include <linux/hwmon.h>
19#include <linux/err.h>
20#include <linux/sched.h>
21#include <linux/delay.h>
22#include <linux/input.h>
23#include <linux/input/touchscreen.h>
24#include <linux/interrupt.h>
25#include <linux/slab.h>
26#include <linux/pm.h>
27#include <linux/property.h>
28#include <linux/gpio/consumer.h>
29#include <linux/spi/spi.h>
30#include <linux/spi/ads7846.h>
31#include <linux/regulator/consumer.h>
32#include <linux/module.h>
33#include <asm/unaligned.h>
34
35/*
36 * This code has been heavily tested on a Nokia 770, and lightly
37 * tested on other ads7846 devices (OSK/Mistral, Lubbock, Spitz).
38 * TSC2046 is just newer ads7846 silicon.
39 * Support for ads7843 tested on Atmel at91sam926x-EK.
40 * Support for ads7845 has only been stubbed in.
41 * Support for Analog Devices AD7873 and AD7843 tested.
42 *
43 * IRQ handling needs a workaround because of a shortcoming in handling
44 * edge triggered IRQs on some platforms like the OMAP1/2. These
45 * platforms don't handle the ARM lazy IRQ disabling properly, thus we
46 * have to maintain our own SW IRQ disabled status. This should be
47 * removed as soon as the affected platform's IRQ handling is fixed.
48 *
49 * App note sbaa036 talks in more detail about accurate sampling...
50 * that ought to help in situations like LCDs inducing noise (which
51 * can also be helped by using synch signals) and more generally.
52 * This driver tries to utilize the measures described in the app
53 * note. The strength of filtering can be set in the board-* specific
54 * files.
55 */
56
57#define TS_POLL_DELAY 1 /* ms delay before the first sample */
58#define TS_POLL_PERIOD 5 /* ms delay between samples */
59
60/* this driver doesn't aim at the peak continuous sample rate */
61#define SAMPLE_BITS (8 /*cmd*/ + 16 /*sample*/ + 2 /* before, after */)
62
63struct ads7846_buf {
64 u8 cmd;
65 __be16 data;
66} __packed;
67
68struct ads7846_buf_layout {
69 unsigned int offset;
70 unsigned int count;
71 unsigned int skip;
72};
73
74/*
75 * We allocate this separately to avoid cache line sharing issues when
76 * driver is used with DMA-based SPI controllers (like atmel_spi) on
77 * systems where main memory is not DMA-coherent (most non-x86 boards).
78 */
79struct ads7846_packet {
80 unsigned int count;
81 unsigned int count_skip;
82 unsigned int cmds;
83 unsigned int last_cmd_idx;
84 struct ads7846_buf_layout l[5];
85 struct ads7846_buf *rx;
86 struct ads7846_buf *tx;
87
88 struct ads7846_buf pwrdown_cmd;
89
90 bool ignore;
91 u16 x, y, z1, z2;
92};
93
94struct ads7846 {
95 struct input_dev *input;
96 char phys[32];
97 char name[32];
98
99 struct spi_device *spi;
100 struct regulator *reg;
101
102 u16 model;
103 u16 vref_mv;
104 u16 vref_delay_usecs;
105 u16 x_plate_ohms;
106 u16 pressure_max;
107
108 bool swap_xy;
109 bool use_internal;
110
111 struct ads7846_packet *packet;
112
113 struct spi_transfer xfer[18];
114 struct spi_message msg[5];
115 int msg_count;
116 wait_queue_head_t wait;
117
118 bool pendown;
119
120 int read_cnt;
121 int read_rep;
122 int last_read;
123
124 u16 debounce_max;
125 u16 debounce_tol;
126 u16 debounce_rep;
127
128 u16 penirq_recheck_delay_usecs;
129
130 struct touchscreen_properties core_prop;
131
132 struct mutex lock;
133 bool stopped; /* P: lock */
134 bool disabled; /* P: lock */
135 bool suspended; /* P: lock */
136
137 int (*filter)(void *data, int data_idx, int *val);
138 void *filter_data;
139 int (*get_pendown_state)(void);
140 struct gpio_desc *gpio_pendown;
141
142 void (*wait_for_sync)(void);
143};
144
145enum ads7846_filter {
146 ADS7846_FILTER_OK,
147 ADS7846_FILTER_REPEAT,
148 ADS7846_FILTER_IGNORE,
149};
150
151/* leave chip selected when we're done, for quicker re-select? */
152#if 0
153#define CS_CHANGE(xfer) ((xfer).cs_change = 1)
154#else
155#define CS_CHANGE(xfer) ((xfer).cs_change = 0)
156#endif
157
158/*--------------------------------------------------------------------------*/
159
160/* The ADS7846 has touchscreen and other sensors.
161 * Earlier ads784x chips are somewhat compatible.
162 */
163#define ADS_START (1 << 7)
164#define ADS_A2A1A0_d_y (1 << 4) /* differential */
165#define ADS_A2A1A0_d_z1 (3 << 4) /* differential */
166#define ADS_A2A1A0_d_z2 (4 << 4) /* differential */
167#define ADS_A2A1A0_d_x (5 << 4) /* differential */
168#define ADS_A2A1A0_temp0 (0 << 4) /* non-differential */
169#define ADS_A2A1A0_vbatt (2 << 4) /* non-differential */
170#define ADS_A2A1A0_vaux (6 << 4) /* non-differential */
171#define ADS_A2A1A0_temp1 (7 << 4) /* non-differential */
172#define ADS_8_BIT (1 << 3)
173#define ADS_12_BIT (0 << 3)
174#define ADS_SER (1 << 2) /* non-differential */
175#define ADS_DFR (0 << 2) /* differential */
176#define ADS_PD10_PDOWN (0 << 0) /* low power mode + penirq */
177#define ADS_PD10_ADC_ON (1 << 0) /* ADC on */
178#define ADS_PD10_REF_ON (2 << 0) /* vREF on + penirq */
179#define ADS_PD10_ALL_ON (3 << 0) /* ADC + vREF on */
180
181#define MAX_12BIT ((1<<12)-1)
182
183/* leave ADC powered up (disables penirq) between differential samples */
184#define READ_12BIT_DFR(x, adc, vref) (ADS_START | ADS_A2A1A0_d_ ## x \
185 | ADS_12_BIT | ADS_DFR | \
186 (adc ? ADS_PD10_ADC_ON : 0) | (vref ? ADS_PD10_REF_ON : 0))
187
188#define READ_Y(vref) (READ_12BIT_DFR(y, 1, vref))
189#define READ_Z1(vref) (READ_12BIT_DFR(z1, 1, vref))
190#define READ_Z2(vref) (READ_12BIT_DFR(z2, 1, vref))
191#define READ_X(vref) (READ_12BIT_DFR(x, 1, vref))
192#define PWRDOWN (READ_12BIT_DFR(y, 0, 0)) /* LAST */
193
194/* single-ended samples need to first power up reference voltage;
195 * we leave both ADC and VREF powered
196 */
197#define READ_12BIT_SER(x) (ADS_START | ADS_A2A1A0_ ## x \
198 | ADS_12_BIT | ADS_SER)
199
200#define REF_ON (READ_12BIT_DFR(x, 1, 1))
201#define REF_OFF (READ_12BIT_DFR(y, 0, 0))
202
203/* Order commands in the most optimal way to reduce Vref switching and
204 * settling time:
205 * Measure: X; Vref: X+, X-; IN: Y+
206 * Measure: Y; Vref: Y+, Y-; IN: X+
207 * Measure: Z1; Vref: Y+, X-; IN: X+
208 * Measure: Z2; Vref: Y+, X-; IN: Y-
209 */
210enum ads7846_cmds {
211 ADS7846_X,
212 ADS7846_Y,
213 ADS7846_Z1,
214 ADS7846_Z2,
215 ADS7846_PWDOWN,
216};
217
218static int get_pendown_state(struct ads7846 *ts)
219{
220 if (ts->get_pendown_state)
221 return ts->get_pendown_state();
222
223 return gpiod_get_value(ts->gpio_pendown);
224}
225
226static void ads7846_report_pen_up(struct ads7846 *ts)
227{
228 struct input_dev *input = ts->input;
229
230 input_report_key(input, BTN_TOUCH, 0);
231 input_report_abs(input, ABS_PRESSURE, 0);
232 input_sync(input);
233
234 ts->pendown = false;
235 dev_vdbg(&ts->spi->dev, "UP\n");
236}
237
238/* Must be called with ts->lock held */
239static void ads7846_stop(struct ads7846 *ts)
240{
241 if (!ts->disabled && !ts->suspended) {
242 /* Signal IRQ thread to stop polling and disable the handler. */
243 ts->stopped = true;
244 mb();
245 wake_up(&ts->wait);
246 disable_irq(ts->spi->irq);
247 }
248}
249
250/* Must be called with ts->lock held */
251static void ads7846_restart(struct ads7846 *ts)
252{
253 if (!ts->disabled && !ts->suspended) {
254 /* Check if pen was released since last stop */
255 if (ts->pendown && !get_pendown_state(ts))
256 ads7846_report_pen_up(ts);
257
258 /* Tell IRQ thread that it may poll the device. */
259 ts->stopped = false;
260 mb();
261 enable_irq(ts->spi->irq);
262 }
263}
264
265/* Must be called with ts->lock held */
266static void __ads7846_disable(struct ads7846 *ts)
267{
268 ads7846_stop(ts);
269 regulator_disable(ts->reg);
270
271 /*
272 * We know the chip's in low power mode since we always
273 * leave it that way after every request
274 */
275}
276
277/* Must be called with ts->lock held */
278static void __ads7846_enable(struct ads7846 *ts)
279{
280 int error;
281
282 error = regulator_enable(ts->reg);
283 if (error != 0)
284 dev_err(&ts->spi->dev, "Failed to enable supply: %d\n", error);
285
286 ads7846_restart(ts);
287}
288
289static void ads7846_disable(struct ads7846 *ts)
290{
291 mutex_lock(&ts->lock);
292
293 if (!ts->disabled) {
294
295 if (!ts->suspended)
296 __ads7846_disable(ts);
297
298 ts->disabled = true;
299 }
300
301 mutex_unlock(&ts->lock);
302}
303
304static void ads7846_enable(struct ads7846 *ts)
305{
306 mutex_lock(&ts->lock);
307
308 if (ts->disabled) {
309
310 ts->disabled = false;
311
312 if (!ts->suspended)
313 __ads7846_enable(ts);
314 }
315
316 mutex_unlock(&ts->lock);
317}
318
319/*--------------------------------------------------------------------------*/
320
321/*
322 * Non-touchscreen sensors only use single-ended conversions.
323 * The range is GND..vREF. The ads7843 and ads7835 must use external vREF;
324 * ads7846 lets that pin be unconnected, to use internal vREF.
325 */
326
327struct ser_req {
328 u8 ref_on;
329 u8 command;
330 u8 ref_off;
331 u16 scratch;
332 struct spi_message msg;
333 struct spi_transfer xfer[6];
334 /*
335 * DMA (thus cache coherency maintenance) requires the
336 * transfer buffers to live in their own cache lines.
337 */
338 __be16 sample ____cacheline_aligned;
339};
340
341struct ads7845_ser_req {
342 u8 command[3];
343 struct spi_message msg;
344 struct spi_transfer xfer[2];
345 /*
346 * DMA (thus cache coherency maintenance) requires the
347 * transfer buffers to live in their own cache lines.
348 */
349 u8 sample[3] ____cacheline_aligned;
350};
351
352static int ads7846_read12_ser(struct device *dev, unsigned command)
353{
354 struct spi_device *spi = to_spi_device(dev);
355 struct ads7846 *ts = dev_get_drvdata(dev);
356 struct ser_req *req;
357 int status;
358
359 req = kzalloc(sizeof *req, GFP_KERNEL);
360 if (!req)
361 return -ENOMEM;
362
363 spi_message_init(&req->msg);
364
365 /* maybe turn on internal vREF, and let it settle */
366 if (ts->use_internal) {
367 req->ref_on = REF_ON;
368 req->xfer[0].tx_buf = &req->ref_on;
369 req->xfer[0].len = 1;
370 spi_message_add_tail(&req->xfer[0], &req->msg);
371
372 req->xfer[1].rx_buf = &req->scratch;
373 req->xfer[1].len = 2;
374
375 /* for 1uF, settle for 800 usec; no cap, 100 usec. */
376 req->xfer[1].delay.value = ts->vref_delay_usecs;
377 req->xfer[1].delay.unit = SPI_DELAY_UNIT_USECS;
378 spi_message_add_tail(&req->xfer[1], &req->msg);
379
380 /* Enable reference voltage */
381 command |= ADS_PD10_REF_ON;
382 }
383
384 /* Enable ADC in every case */
385 command |= ADS_PD10_ADC_ON;
386
387 /* take sample */
388 req->command = (u8) command;
389 req->xfer[2].tx_buf = &req->command;
390 req->xfer[2].len = 1;
391 spi_message_add_tail(&req->xfer[2], &req->msg);
392
393 req->xfer[3].rx_buf = &req->sample;
394 req->xfer[3].len = 2;
395 spi_message_add_tail(&req->xfer[3], &req->msg);
396
397 /* REVISIT: take a few more samples, and compare ... */
398
399 /* converter in low power mode & enable PENIRQ */
400 req->ref_off = PWRDOWN;
401 req->xfer[4].tx_buf = &req->ref_off;
402 req->xfer[4].len = 1;
403 spi_message_add_tail(&req->xfer[4], &req->msg);
404
405 req->xfer[5].rx_buf = &req->scratch;
406 req->xfer[5].len = 2;
407 CS_CHANGE(req->xfer[5]);
408 spi_message_add_tail(&req->xfer[5], &req->msg);
409
410 mutex_lock(&ts->lock);
411 ads7846_stop(ts);
412 status = spi_sync(spi, &req->msg);
413 ads7846_restart(ts);
414 mutex_unlock(&ts->lock);
415
416 if (status == 0) {
417 /* on-wire is a must-ignore bit, a BE12 value, then padding */
418 status = be16_to_cpu(req->sample);
419 status = status >> 3;
420 status &= 0x0fff;
421 }
422
423 kfree(req);
424 return status;
425}
426
427static int ads7845_read12_ser(struct device *dev, unsigned command)
428{
429 struct spi_device *spi = to_spi_device(dev);
430 struct ads7846 *ts = dev_get_drvdata(dev);
431 struct ads7845_ser_req *req;
432 int status;
433
434 req = kzalloc(sizeof *req, GFP_KERNEL);
435 if (!req)
436 return -ENOMEM;
437
438 spi_message_init(&req->msg);
439
440 req->command[0] = (u8) command;
441 req->xfer[0].tx_buf = req->command;
442 req->xfer[0].rx_buf = req->sample;
443 req->xfer[0].len = 3;
444 spi_message_add_tail(&req->xfer[0], &req->msg);
445
446 mutex_lock(&ts->lock);
447 ads7846_stop(ts);
448 status = spi_sync(spi, &req->msg);
449 ads7846_restart(ts);
450 mutex_unlock(&ts->lock);
451
452 if (status == 0) {
453 /* BE12 value, then padding */
454 status = get_unaligned_be16(&req->sample[1]);
455 status = status >> 3;
456 status &= 0x0fff;
457 }
458
459 kfree(req);
460 return status;
461}
462
463#if IS_ENABLED(CONFIG_HWMON)
464
465#define SHOW(name, var, adjust) static ssize_t \
466name ## _show(struct device *dev, struct device_attribute *attr, char *buf) \
467{ \
468 struct ads7846 *ts = dev_get_drvdata(dev); \
469 ssize_t v = ads7846_read12_ser(&ts->spi->dev, \
470 READ_12BIT_SER(var)); \
471 if (v < 0) \
472 return v; \
473 return sprintf(buf, "%u\n", adjust(ts, v)); \
474} \
475static DEVICE_ATTR(name, S_IRUGO, name ## _show, NULL);
476
477
478/* Sysfs conventions report temperatures in millidegrees Celsius.
479 * ADS7846 could use the low-accuracy two-sample scheme, but can't do the high
480 * accuracy scheme without calibration data. For now we won't try either;
481 * userspace sees raw sensor values, and must scale/calibrate appropriately.
482 */
483static inline unsigned null_adjust(struct ads7846 *ts, ssize_t v)
484{
485 return v;
486}
487
488SHOW(temp0, temp0, null_adjust) /* temp1_input */
489SHOW(temp1, temp1, null_adjust) /* temp2_input */
490
491
492/* sysfs conventions report voltages in millivolts. We can convert voltages
493 * if we know vREF. userspace may need to scale vAUX to match the board's
494 * external resistors; we assume that vBATT only uses the internal ones.
495 */
496static inline unsigned vaux_adjust(struct ads7846 *ts, ssize_t v)
497{
498 unsigned retval = v;
499
500 /* external resistors may scale vAUX into 0..vREF */
501 retval *= ts->vref_mv;
502 retval = retval >> 12;
503
504 return retval;
505}
506
507static inline unsigned vbatt_adjust(struct ads7846 *ts, ssize_t v)
508{
509 unsigned retval = vaux_adjust(ts, v);
510
511 /* ads7846 has a resistor ladder to scale this signal down */
512 if (ts->model == 7846)
513 retval *= 4;
514
515 return retval;
516}
517
518SHOW(in0_input, vaux, vaux_adjust)
519SHOW(in1_input, vbatt, vbatt_adjust)
520
521static umode_t ads7846_is_visible(struct kobject *kobj, struct attribute *attr,
522 int index)
523{
524 struct device *dev = kobj_to_dev(kobj);
525 struct ads7846 *ts = dev_get_drvdata(dev);
526
527 if (ts->model == 7843 && index < 2) /* in0, in1 */
528 return 0;
529 if (ts->model == 7845 && index != 2) /* in0 */
530 return 0;
531
532 return attr->mode;
533}
534
535static struct attribute *ads7846_attributes[] = {
536 &dev_attr_temp0.attr, /* 0 */
537 &dev_attr_temp1.attr, /* 1 */
538 &dev_attr_in0_input.attr, /* 2 */
539 &dev_attr_in1_input.attr, /* 3 */
540 NULL,
541};
542
543static const struct attribute_group ads7846_attr_group = {
544 .attrs = ads7846_attributes,
545 .is_visible = ads7846_is_visible,
546};
547__ATTRIBUTE_GROUPS(ads7846_attr);
548
549static int ads784x_hwmon_register(struct spi_device *spi, struct ads7846 *ts)
550{
551 struct device *hwmon;
552
553 /* hwmon sensors need a reference voltage */
554 switch (ts->model) {
555 case 7846:
556 if (!ts->vref_mv) {
557 dev_dbg(&spi->dev, "assuming 2.5V internal vREF\n");
558 ts->vref_mv = 2500;
559 ts->use_internal = true;
560 }
561 break;
562 case 7845:
563 case 7843:
564 if (!ts->vref_mv) {
565 dev_warn(&spi->dev,
566 "external vREF for ADS%d not specified\n",
567 ts->model);
568 return 0;
569 }
570 break;
571 }
572
573 hwmon = devm_hwmon_device_register_with_groups(&spi->dev,
574 spi->modalias, ts,
575 ads7846_attr_groups);
576
577 return PTR_ERR_OR_ZERO(hwmon);
578}
579
580#else
581static inline int ads784x_hwmon_register(struct spi_device *spi,
582 struct ads7846 *ts)
583{
584 return 0;
585}
586#endif
587
588static ssize_t ads7846_pen_down_show(struct device *dev,
589 struct device_attribute *attr, char *buf)
590{
591 struct ads7846 *ts = dev_get_drvdata(dev);
592
593 return sprintf(buf, "%u\n", ts->pendown);
594}
595
596static DEVICE_ATTR(pen_down, S_IRUGO, ads7846_pen_down_show, NULL);
597
598static ssize_t ads7846_disable_show(struct device *dev,
599 struct device_attribute *attr, char *buf)
600{
601 struct ads7846 *ts = dev_get_drvdata(dev);
602
603 return sprintf(buf, "%u\n", ts->disabled);
604}
605
606static ssize_t ads7846_disable_store(struct device *dev,
607 struct device_attribute *attr,
608 const char *buf, size_t count)
609{
610 struct ads7846 *ts = dev_get_drvdata(dev);
611 unsigned int i;
612 int err;
613
614 err = kstrtouint(buf, 10, &i);
615 if (err)
616 return err;
617
618 if (i)
619 ads7846_disable(ts);
620 else
621 ads7846_enable(ts);
622
623 return count;
624}
625
626static DEVICE_ATTR(disable, 0664, ads7846_disable_show, ads7846_disable_store);
627
628static struct attribute *ads784x_attrs[] = {
629 &dev_attr_pen_down.attr,
630 &dev_attr_disable.attr,
631 NULL,
632};
633ATTRIBUTE_GROUPS(ads784x);
634
635/*--------------------------------------------------------------------------*/
636
637static void null_wait_for_sync(void)
638{
639}
640
641static int ads7846_debounce_filter(void *ads, int data_idx, int *val)
642{
643 struct ads7846 *ts = ads;
644
645 if (!ts->read_cnt || (abs(ts->last_read - *val) > ts->debounce_tol)) {
646 /* Start over collecting consistent readings. */
647 ts->read_rep = 0;
648 /*
649 * Repeat it, if this was the first read or the read
650 * wasn't consistent enough.
651 */
652 if (ts->read_cnt < ts->debounce_max) {
653 ts->last_read = *val;
654 ts->read_cnt++;
655 return ADS7846_FILTER_REPEAT;
656 } else {
657 /*
658 * Maximum number of debouncing reached and still
659 * not enough number of consistent readings. Abort
660 * the whole sample, repeat it in the next sampling
661 * period.
662 */
663 ts->read_cnt = 0;
664 return ADS7846_FILTER_IGNORE;
665 }
666 } else {
667 if (++ts->read_rep > ts->debounce_rep) {
668 /*
669 * Got a good reading for this coordinate,
670 * go for the next one.
671 */
672 ts->read_cnt = 0;
673 ts->read_rep = 0;
674 return ADS7846_FILTER_OK;
675 } else {
676 /* Read more values that are consistent. */
677 ts->read_cnt++;
678 return ADS7846_FILTER_REPEAT;
679 }
680 }
681}
682
683static int ads7846_no_filter(void *ads, int data_idx, int *val)
684{
685 return ADS7846_FILTER_OK;
686}
687
688static int ads7846_get_value(struct ads7846_buf *buf)
689{
690 int value;
691
692 value = be16_to_cpup(&buf->data);
693
694 /* enforce ADC output is 12 bits width */
695 return (value >> 3) & 0xfff;
696}
697
698static void ads7846_set_cmd_val(struct ads7846 *ts, enum ads7846_cmds cmd_idx,
699 u16 val)
700{
701 struct ads7846_packet *packet = ts->packet;
702
703 switch (cmd_idx) {
704 case ADS7846_Y:
705 packet->y = val;
706 break;
707 case ADS7846_X:
708 packet->x = val;
709 break;
710 case ADS7846_Z1:
711 packet->z1 = val;
712 break;
713 case ADS7846_Z2:
714 packet->z2 = val;
715 break;
716 default:
717 WARN_ON_ONCE(1);
718 }
719}
720
721static u8 ads7846_get_cmd(enum ads7846_cmds cmd_idx, int vref)
722{
723 switch (cmd_idx) {
724 case ADS7846_Y:
725 return READ_Y(vref);
726 case ADS7846_X:
727 return READ_X(vref);
728
729 /* 7846 specific commands */
730 case ADS7846_Z1:
731 return READ_Z1(vref);
732 case ADS7846_Z2:
733 return READ_Z2(vref);
734 case ADS7846_PWDOWN:
735 return PWRDOWN;
736 default:
737 WARN_ON_ONCE(1);
738 }
739
740 return 0;
741}
742
743static bool ads7846_cmd_need_settle(enum ads7846_cmds cmd_idx)
744{
745 switch (cmd_idx) {
746 case ADS7846_X:
747 case ADS7846_Y:
748 case ADS7846_Z1:
749 case ADS7846_Z2:
750 return true;
751 case ADS7846_PWDOWN:
752 return false;
753 default:
754 WARN_ON_ONCE(1);
755 }
756
757 return false;
758}
759
760static int ads7846_filter(struct ads7846 *ts)
761{
762 struct ads7846_packet *packet = ts->packet;
763 int action;
764 int val;
765 unsigned int cmd_idx, b;
766
767 packet->ignore = false;
768 for (cmd_idx = packet->last_cmd_idx; cmd_idx < packet->cmds - 1; cmd_idx++) {
769 struct ads7846_buf_layout *l = &packet->l[cmd_idx];
770
771 packet->last_cmd_idx = cmd_idx;
772
773 for (b = l->skip; b < l->count; b++) {
774 val = ads7846_get_value(&packet->rx[l->offset + b]);
775
776 action = ts->filter(ts->filter_data, cmd_idx, &val);
777 if (action == ADS7846_FILTER_REPEAT) {
778 if (b == l->count - 1)
779 return -EAGAIN;
780 } else if (action == ADS7846_FILTER_OK) {
781 ads7846_set_cmd_val(ts, cmd_idx, val);
782 break;
783 } else {
784 packet->ignore = true;
785 return 0;
786 }
787 }
788 }
789
790 return 0;
791}
792
793static void ads7846_read_state(struct ads7846 *ts)
794{
795 struct ads7846_packet *packet = ts->packet;
796 struct spi_message *m;
797 int msg_idx = 0;
798 int error;
799
800 packet->last_cmd_idx = 0;
801
802 while (true) {
803 ts->wait_for_sync();
804
805 m = &ts->msg[msg_idx];
806 error = spi_sync(ts->spi, m);
807 if (error) {
808 dev_err(&ts->spi->dev, "spi_sync --> %d\n", error);
809 packet->ignore = true;
810 return;
811 }
812
813 error = ads7846_filter(ts);
814 if (error)
815 continue;
816
817 return;
818 }
819}
820
821static void ads7846_report_state(struct ads7846 *ts)
822{
823 struct ads7846_packet *packet = ts->packet;
824 unsigned int Rt;
825 u16 x, y, z1, z2;
826
827 x = packet->x;
828 y = packet->y;
829 if (ts->model == 7845) {
830 z1 = 0;
831 z2 = 0;
832 } else {
833 z1 = packet->z1;
834 z2 = packet->z2;
835 }
836
837 /* range filtering */
838 if (x == MAX_12BIT)
839 x = 0;
840
841 if (ts->model == 7843 || ts->model == 7845) {
842 Rt = ts->pressure_max / 2;
843 } else if (likely(x && z1)) {
844 /* compute touch pressure resistance using equation #2 */
845 Rt = z2;
846 Rt -= z1;
847 Rt *= ts->x_plate_ohms;
848 Rt = DIV_ROUND_CLOSEST(Rt, 16);
849 Rt *= x;
850 Rt /= z1;
851 Rt = DIV_ROUND_CLOSEST(Rt, 256);
852 } else {
853 Rt = 0;
854 }
855
856 /*
857 * Sample found inconsistent by debouncing or pressure is beyond
858 * the maximum. Don't report it to user space, repeat at least
859 * once more the measurement
860 */
861 if (packet->ignore || Rt > ts->pressure_max) {
862 dev_vdbg(&ts->spi->dev, "ignored %d pressure %d\n",
863 packet->ignore, Rt);
864 return;
865 }
866
867 /*
868 * Maybe check the pendown state before reporting. This discards
869 * false readings when the pen is lifted.
870 */
871 if (ts->penirq_recheck_delay_usecs) {
872 udelay(ts->penirq_recheck_delay_usecs);
873 if (!get_pendown_state(ts))
874 Rt = 0;
875 }
876
877 /*
878 * NOTE: We can't rely on the pressure to determine the pen down
879 * state, even this controller has a pressure sensor. The pressure
880 * value can fluctuate for quite a while after lifting the pen and
881 * in some cases may not even settle at the expected value.
882 *
883 * The only safe way to check for the pen up condition is in the
884 * timer by reading the pen signal state (it's a GPIO _and_ IRQ).
885 */
886 if (Rt) {
887 struct input_dev *input = ts->input;
888
889 if (!ts->pendown) {
890 input_report_key(input, BTN_TOUCH, 1);
891 ts->pendown = true;
892 dev_vdbg(&ts->spi->dev, "DOWN\n");
893 }
894
895 touchscreen_report_pos(input, &ts->core_prop, x, y, false);
896 input_report_abs(input, ABS_PRESSURE, ts->pressure_max - Rt);
897
898 input_sync(input);
899 dev_vdbg(&ts->spi->dev, "%4d/%4d/%4d\n", x, y, Rt);
900 }
901}
902
903static irqreturn_t ads7846_hard_irq(int irq, void *handle)
904{
905 struct ads7846 *ts = handle;
906
907 return get_pendown_state(ts) ? IRQ_WAKE_THREAD : IRQ_HANDLED;
908}
909
910
911static irqreturn_t ads7846_irq(int irq, void *handle)
912{
913 struct ads7846 *ts = handle;
914
915 /* Start with a small delay before checking pendown state */
916 msleep(TS_POLL_DELAY);
917
918 while (!ts->stopped && get_pendown_state(ts)) {
919
920 /* pen is down, continue with the measurement */
921 ads7846_read_state(ts);
922
923 if (!ts->stopped)
924 ads7846_report_state(ts);
925
926 wait_event_timeout(ts->wait, ts->stopped,
927 msecs_to_jiffies(TS_POLL_PERIOD));
928 }
929
930 if (ts->pendown && !ts->stopped)
931 ads7846_report_pen_up(ts);
932
933 return IRQ_HANDLED;
934}
935
936static int ads7846_suspend(struct device *dev)
937{
938 struct ads7846 *ts = dev_get_drvdata(dev);
939
940 mutex_lock(&ts->lock);
941
942 if (!ts->suspended) {
943
944 if (!ts->disabled)
945 __ads7846_disable(ts);
946
947 if (device_may_wakeup(&ts->spi->dev))
948 enable_irq_wake(ts->spi->irq);
949
950 ts->suspended = true;
951 }
952
953 mutex_unlock(&ts->lock);
954
955 return 0;
956}
957
958static int ads7846_resume(struct device *dev)
959{
960 struct ads7846 *ts = dev_get_drvdata(dev);
961
962 mutex_lock(&ts->lock);
963
964 if (ts->suspended) {
965
966 ts->suspended = false;
967
968 if (device_may_wakeup(&ts->spi->dev))
969 disable_irq_wake(ts->spi->irq);
970
971 if (!ts->disabled)
972 __ads7846_enable(ts);
973 }
974
975 mutex_unlock(&ts->lock);
976
977 return 0;
978}
979
980static DEFINE_SIMPLE_DEV_PM_OPS(ads7846_pm, ads7846_suspend, ads7846_resume);
981
982static int ads7846_setup_pendown(struct spi_device *spi,
983 struct ads7846 *ts,
984 const struct ads7846_platform_data *pdata)
985{
986 /*
987 * REVISIT when the irq can be triggered active-low, or if for some
988 * reason the touchscreen isn't hooked up, we don't need to access
989 * the pendown state.
990 */
991
992 if (pdata->get_pendown_state) {
993 ts->get_pendown_state = pdata->get_pendown_state;
994 } else {
995 ts->gpio_pendown = gpiod_get(&spi->dev, "pendown", GPIOD_IN);
996 if (IS_ERR(ts->gpio_pendown)) {
997 dev_err(&spi->dev, "failed to request pendown GPIO\n");
998 return PTR_ERR(ts->gpio_pendown);
999 }
1000 if (pdata->gpio_pendown_debounce)
1001 gpiod_set_debounce(ts->gpio_pendown,
1002 pdata->gpio_pendown_debounce);
1003 }
1004
1005 return 0;
1006}
1007
1008/*
1009 * Set up the transfers to read touchscreen state; this assumes we
1010 * use formula #2 for pressure, not #3.
1011 */
1012static int ads7846_setup_spi_msg(struct ads7846 *ts,
1013 const struct ads7846_platform_data *pdata)
1014{
1015 struct spi_message *m = &ts->msg[0];
1016 struct spi_transfer *x = ts->xfer;
1017 struct ads7846_packet *packet = ts->packet;
1018 int vref = pdata->keep_vref_on;
1019 unsigned int count, offset = 0;
1020 unsigned int cmd_idx, b;
1021 unsigned long time;
1022 size_t size = 0;
1023
1024 /* time per bit */
1025 time = NSEC_PER_SEC / ts->spi->max_speed_hz;
1026
1027 count = pdata->settle_delay_usecs * NSEC_PER_USEC / time;
1028 packet->count_skip = DIV_ROUND_UP(count, 24);
1029
1030 if (ts->debounce_max && ts->debounce_rep)
1031 /* ads7846_debounce_filter() is making ts->debounce_rep + 2
1032 * reads. So we need to get all samples for normal case. */
1033 packet->count = ts->debounce_rep + 2;
1034 else
1035 packet->count = 1;
1036
1037 if (ts->model == 7846)
1038 packet->cmds = 5; /* x, y, z1, z2, pwdown */
1039 else
1040 packet->cmds = 3; /* x, y, pwdown */
1041
1042 for (cmd_idx = 0; cmd_idx < packet->cmds; cmd_idx++) {
1043 struct ads7846_buf_layout *l = &packet->l[cmd_idx];
1044 unsigned int max_count;
1045
1046 if (cmd_idx == packet->cmds - 1)
1047 cmd_idx = ADS7846_PWDOWN;
1048
1049 if (ads7846_cmd_need_settle(cmd_idx))
1050 max_count = packet->count + packet->count_skip;
1051 else
1052 max_count = packet->count;
1053
1054 l->offset = offset;
1055 offset += max_count;
1056 l->count = max_count;
1057 l->skip = packet->count_skip;
1058 size += sizeof(*packet->tx) * max_count;
1059 }
1060
1061 packet->tx = devm_kzalloc(&ts->spi->dev, size, GFP_KERNEL);
1062 if (!packet->tx)
1063 return -ENOMEM;
1064
1065 packet->rx = devm_kzalloc(&ts->spi->dev, size, GFP_KERNEL);
1066 if (!packet->rx)
1067 return -ENOMEM;
1068
1069 if (ts->model == 7873) {
1070 /*
1071 * The AD7873 is almost identical to the ADS7846
1072 * keep VREF off during differential/ratiometric
1073 * conversion modes.
1074 */
1075 ts->model = 7846;
1076 vref = 0;
1077 }
1078
1079 ts->msg_count = 1;
1080 spi_message_init(m);
1081 m->context = ts;
1082
1083 for (cmd_idx = 0; cmd_idx < packet->cmds; cmd_idx++) {
1084 struct ads7846_buf_layout *l = &packet->l[cmd_idx];
1085 u8 cmd;
1086
1087 if (cmd_idx == packet->cmds - 1)
1088 cmd_idx = ADS7846_PWDOWN;
1089
1090 cmd = ads7846_get_cmd(cmd_idx, vref);
1091
1092 for (b = 0; b < l->count; b++)
1093 packet->tx[l->offset + b].cmd = cmd;
1094 }
1095
1096 x->tx_buf = packet->tx;
1097 x->rx_buf = packet->rx;
1098 x->len = size;
1099 spi_message_add_tail(x, m);
1100
1101 return 0;
1102}
1103
1104static const struct of_device_id ads7846_dt_ids[] = {
1105 { .compatible = "ti,tsc2046", .data = (void *) 7846 },
1106 { .compatible = "ti,ads7843", .data = (void *) 7843 },
1107 { .compatible = "ti,ads7845", .data = (void *) 7845 },
1108 { .compatible = "ti,ads7846", .data = (void *) 7846 },
1109 { .compatible = "ti,ads7873", .data = (void *) 7873 },
1110 { }
1111};
1112MODULE_DEVICE_TABLE(of, ads7846_dt_ids);
1113
1114static const struct ads7846_platform_data *ads7846_get_props(struct device *dev)
1115{
1116 struct ads7846_platform_data *pdata;
1117 u32 value;
1118
1119 pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
1120 if (!pdata)
1121 return ERR_PTR(-ENOMEM);
1122
1123 pdata->model = (uintptr_t)device_get_match_data(dev);
1124
1125 device_property_read_u16(dev, "ti,vref-delay-usecs",
1126 &pdata->vref_delay_usecs);
1127 device_property_read_u16(dev, "ti,vref-mv", &pdata->vref_mv);
1128 pdata->keep_vref_on = device_property_read_bool(dev, "ti,keep-vref-on");
1129
1130 pdata->swap_xy = device_property_read_bool(dev, "ti,swap-xy");
1131
1132 device_property_read_u16(dev, "ti,settle-delay-usec",
1133 &pdata->settle_delay_usecs);
1134 device_property_read_u16(dev, "ti,penirq-recheck-delay-usecs",
1135 &pdata->penirq_recheck_delay_usecs);
1136
1137 device_property_read_u16(dev, "ti,x-plate-ohms", &pdata->x_plate_ohms);
1138 device_property_read_u16(dev, "ti,y-plate-ohms", &pdata->y_plate_ohms);
1139
1140 device_property_read_u16(dev, "ti,x-min", &pdata->x_min);
1141 device_property_read_u16(dev, "ti,y-min", &pdata->y_min);
1142 device_property_read_u16(dev, "ti,x-max", &pdata->x_max);
1143 device_property_read_u16(dev, "ti,y-max", &pdata->y_max);
1144
1145 /*
1146 * touchscreen-max-pressure gets parsed during
1147 * touchscreen_parse_properties()
1148 */
1149 device_property_read_u16(dev, "ti,pressure-min", &pdata->pressure_min);
1150 if (!device_property_read_u32(dev, "touchscreen-min-pressure", &value))
1151 pdata->pressure_min = (u16) value;
1152 device_property_read_u16(dev, "ti,pressure-max", &pdata->pressure_max);
1153
1154 device_property_read_u16(dev, "ti,debounce-max", &pdata->debounce_max);
1155 if (!device_property_read_u32(dev, "touchscreen-average-samples", &value))
1156 pdata->debounce_max = (u16) value;
1157 device_property_read_u16(dev, "ti,debounce-tol", &pdata->debounce_tol);
1158 device_property_read_u16(dev, "ti,debounce-rep", &pdata->debounce_rep);
1159
1160 device_property_read_u32(dev, "ti,pendown-gpio-debounce",
1161 &pdata->gpio_pendown_debounce);
1162
1163 pdata->wakeup = device_property_read_bool(dev, "wakeup-source") ||
1164 device_property_read_bool(dev, "linux,wakeup");
1165
1166 return pdata;
1167}
1168
1169static void ads7846_regulator_disable(void *regulator)
1170{
1171 regulator_disable(regulator);
1172}
1173
1174static int ads7846_probe(struct spi_device *spi)
1175{
1176 const struct ads7846_platform_data *pdata;
1177 struct ads7846 *ts;
1178 struct device *dev = &spi->dev;
1179 struct ads7846_packet *packet;
1180 struct input_dev *input_dev;
1181 unsigned long irq_flags;
1182 int err;
1183
1184 if (!spi->irq) {
1185 dev_dbg(dev, "no IRQ?\n");
1186 return -EINVAL;
1187 }
1188
1189 /* don't exceed max specified sample rate */
1190 if (spi->max_speed_hz > (125000 * SAMPLE_BITS)) {
1191 dev_err(dev, "f(sample) %d KHz?\n",
1192 (spi->max_speed_hz/SAMPLE_BITS)/1000);
1193 return -EINVAL;
1194 }
1195
1196 /*
1197 * We'd set TX word size 8 bits and RX word size to 13 bits ... except
1198 * that even if the hardware can do that, the SPI controller driver
1199 * may not. So we stick to very-portable 8 bit words, both RX and TX.
1200 */
1201 spi->bits_per_word = 8;
1202 spi->mode &= ~SPI_MODE_X_MASK;
1203 spi->mode |= SPI_MODE_0;
1204 err = spi_setup(spi);
1205 if (err < 0)
1206 return err;
1207
1208 ts = devm_kzalloc(dev, sizeof(struct ads7846), GFP_KERNEL);
1209 if (!ts)
1210 return -ENOMEM;
1211
1212 packet = devm_kzalloc(dev, sizeof(struct ads7846_packet), GFP_KERNEL);
1213 if (!packet)
1214 return -ENOMEM;
1215
1216 input_dev = devm_input_allocate_device(dev);
1217 if (!input_dev)
1218 return -ENOMEM;
1219
1220 spi_set_drvdata(spi, ts);
1221
1222 ts->packet = packet;
1223 ts->spi = spi;
1224 ts->input = input_dev;
1225
1226 mutex_init(&ts->lock);
1227 init_waitqueue_head(&ts->wait);
1228
1229 pdata = dev_get_platdata(dev);
1230 if (!pdata) {
1231 pdata = ads7846_get_props(dev);
1232 if (IS_ERR(pdata))
1233 return PTR_ERR(pdata);
1234 }
1235
1236 ts->model = pdata->model ? : 7846;
1237 ts->vref_delay_usecs = pdata->vref_delay_usecs ? : 100;
1238 ts->x_plate_ohms = pdata->x_plate_ohms ? : 400;
1239 ts->vref_mv = pdata->vref_mv;
1240
1241 if (pdata->debounce_max) {
1242 ts->debounce_max = pdata->debounce_max;
1243 if (ts->debounce_max < 2)
1244 ts->debounce_max = 2;
1245 ts->debounce_tol = pdata->debounce_tol;
1246 ts->debounce_rep = pdata->debounce_rep;
1247 ts->filter = ads7846_debounce_filter;
1248 ts->filter_data = ts;
1249 } else {
1250 ts->filter = ads7846_no_filter;
1251 }
1252
1253 err = ads7846_setup_pendown(spi, ts, pdata);
1254 if (err)
1255 return err;
1256
1257 if (pdata->penirq_recheck_delay_usecs)
1258 ts->penirq_recheck_delay_usecs =
1259 pdata->penirq_recheck_delay_usecs;
1260
1261 ts->wait_for_sync = pdata->wait_for_sync ? : null_wait_for_sync;
1262
1263 snprintf(ts->phys, sizeof(ts->phys), "%s/input0", dev_name(dev));
1264 snprintf(ts->name, sizeof(ts->name), "ADS%d Touchscreen", ts->model);
1265
1266 input_dev->name = ts->name;
1267 input_dev->phys = ts->phys;
1268
1269 input_dev->id.bustype = BUS_SPI;
1270 input_dev->id.product = pdata->model;
1271
1272 input_set_capability(input_dev, EV_KEY, BTN_TOUCH);
1273 input_set_abs_params(input_dev, ABS_X,
1274 pdata->x_min ? : 0,
1275 pdata->x_max ? : MAX_12BIT,
1276 0, 0);
1277 input_set_abs_params(input_dev, ABS_Y,
1278 pdata->y_min ? : 0,
1279 pdata->y_max ? : MAX_12BIT,
1280 0, 0);
1281 if (ts->model != 7845)
1282 input_set_abs_params(input_dev, ABS_PRESSURE,
1283 pdata->pressure_min, pdata->pressure_max, 0, 0);
1284
1285 /*
1286 * Parse common framework properties. Must be done here to ensure the
1287 * correct behaviour in case of using the legacy vendor bindings. The
1288 * general binding value overrides the vendor specific one.
1289 */
1290 touchscreen_parse_properties(ts->input, false, &ts->core_prop);
1291 ts->pressure_max = input_abs_get_max(input_dev, ABS_PRESSURE) ? : ~0;
1292
1293 /*
1294 * Check if legacy ti,swap-xy binding is used instead of
1295 * touchscreen-swapped-x-y
1296 */
1297 if (!ts->core_prop.swap_x_y && pdata->swap_xy) {
1298 swap(input_dev->absinfo[ABS_X], input_dev->absinfo[ABS_Y]);
1299 ts->core_prop.swap_x_y = true;
1300 }
1301
1302 ads7846_setup_spi_msg(ts, pdata);
1303
1304 ts->reg = devm_regulator_get(dev, "vcc");
1305 if (IS_ERR(ts->reg)) {
1306 err = PTR_ERR(ts->reg);
1307 dev_err(dev, "unable to get regulator: %d\n", err);
1308 return err;
1309 }
1310
1311 err = regulator_enable(ts->reg);
1312 if (err) {
1313 dev_err(dev, "unable to enable regulator: %d\n", err);
1314 return err;
1315 }
1316
1317 err = devm_add_action_or_reset(dev, ads7846_regulator_disable, ts->reg);
1318 if (err)
1319 return err;
1320
1321 irq_flags = pdata->irq_flags ? : IRQF_TRIGGER_FALLING;
1322 irq_flags |= IRQF_ONESHOT;
1323
1324 err = devm_request_threaded_irq(dev, spi->irq,
1325 ads7846_hard_irq, ads7846_irq,
1326 irq_flags, dev->driver->name, ts);
1327 if (err && err != -EPROBE_DEFER && !pdata->irq_flags) {
1328 dev_info(dev,
1329 "trying pin change workaround on irq %d\n", spi->irq);
1330 irq_flags |= IRQF_TRIGGER_RISING;
1331 err = devm_request_threaded_irq(dev, spi->irq,
1332 ads7846_hard_irq, ads7846_irq,
1333 irq_flags, dev->driver->name,
1334 ts);
1335 }
1336
1337 if (err) {
1338 dev_dbg(dev, "irq %d busy?\n", spi->irq);
1339 return err;
1340 }
1341
1342 err = ads784x_hwmon_register(spi, ts);
1343 if (err)
1344 return err;
1345
1346 dev_info(dev, "touchscreen, irq %d\n", spi->irq);
1347
1348 /*
1349 * Take a first sample, leaving nPENIRQ active and vREF off; avoid
1350 * the touchscreen, in case it's not connected.
1351 */
1352 if (ts->model == 7845)
1353 ads7845_read12_ser(dev, PWRDOWN);
1354 else
1355 (void) ads7846_read12_ser(dev, READ_12BIT_SER(vaux));
1356
1357 err = input_register_device(input_dev);
1358 if (err)
1359 return err;
1360
1361 device_init_wakeup(dev, pdata->wakeup);
1362
1363 /*
1364 * If device does not carry platform data we must have allocated it
1365 * when parsing DT data.
1366 */
1367 if (!dev_get_platdata(dev))
1368 devm_kfree(dev, (void *)pdata);
1369
1370 return 0;
1371}
1372
1373static void ads7846_remove(struct spi_device *spi)
1374{
1375 struct ads7846 *ts = spi_get_drvdata(spi);
1376
1377 ads7846_stop(ts);
1378}
1379
1380static struct spi_driver ads7846_driver = {
1381 .driver = {
1382 .name = "ads7846",
1383 .dev_groups = ads784x_groups,
1384 .pm = pm_sleep_ptr(&ads7846_pm),
1385 .of_match_table = ads7846_dt_ids,
1386 },
1387 .probe = ads7846_probe,
1388 .remove = ads7846_remove,
1389};
1390
1391module_spi_driver(ads7846_driver);
1392
1393MODULE_DESCRIPTION("ADS7846 TouchScreen Driver");
1394MODULE_LICENSE("GPL");
1395MODULE_ALIAS("spi:ads7846");
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * ADS7846 based touchscreen and sensor driver
4 *
5 * Copyright (c) 2005 David Brownell
6 * Copyright (c) 2006 Nokia Corporation
7 * Various changes: Imre Deak <imre.deak@nokia.com>
8 *
9 * Using code from:
10 * - corgi_ts.c
11 * Copyright (C) 2004-2005 Richard Purdie
12 * - omap_ts.[hc], ads7846.h, ts_osk.c
13 * Copyright (C) 2002 MontaVista Software
14 * Copyright (C) 2004 Texas Instruments
15 * Copyright (C) 2005 Dirk Behme
16 */
17#include <linux/types.h>
18#include <linux/hwmon.h>
19#include <linux/err.h>
20#include <linux/sched.h>
21#include <linux/delay.h>
22#include <linux/input.h>
23#include <linux/input/touchscreen.h>
24#include <linux/interrupt.h>
25#include <linux/slab.h>
26#include <linux/pm.h>
27#include <linux/of.h>
28#include <linux/of_gpio.h>
29#include <linux/of_device.h>
30#include <linux/gpio.h>
31#include <linux/spi/spi.h>
32#include <linux/spi/ads7846.h>
33#include <linux/regulator/consumer.h>
34#include <linux/module.h>
35#include <asm/unaligned.h>
36
37/*
38 * This code has been heavily tested on a Nokia 770, and lightly
39 * tested on other ads7846 devices (OSK/Mistral, Lubbock, Spitz).
40 * TSC2046 is just newer ads7846 silicon.
41 * Support for ads7843 tested on Atmel at91sam926x-EK.
42 * Support for ads7845 has only been stubbed in.
43 * Support for Analog Devices AD7873 and AD7843 tested.
44 *
45 * IRQ handling needs a workaround because of a shortcoming in handling
46 * edge triggered IRQs on some platforms like the OMAP1/2. These
47 * platforms don't handle the ARM lazy IRQ disabling properly, thus we
48 * have to maintain our own SW IRQ disabled status. This should be
49 * removed as soon as the affected platform's IRQ handling is fixed.
50 *
51 * App note sbaa036 talks in more detail about accurate sampling...
52 * that ought to help in situations like LCDs inducing noise (which
53 * can also be helped by using synch signals) and more generally.
54 * This driver tries to utilize the measures described in the app
55 * note. The strength of filtering can be set in the board-* specific
56 * files.
57 */
58
59#define TS_POLL_DELAY 1 /* ms delay before the first sample */
60#define TS_POLL_PERIOD 5 /* ms delay between samples */
61
62/* this driver doesn't aim at the peak continuous sample rate */
63#define SAMPLE_BITS (8 /*cmd*/ + 16 /*sample*/ + 2 /* before, after */)
64
65struct ads7846_buf {
66 u8 cmd;
67 __be16 data;
68} __packed;
69
70struct ads7846_buf_layout {
71 unsigned int offset;
72 unsigned int count;
73 unsigned int skip;
74};
75
76/*
77 * We allocate this separately to avoid cache line sharing issues when
78 * driver is used with DMA-based SPI controllers (like atmel_spi) on
79 * systems where main memory is not DMA-coherent (most non-x86 boards).
80 */
81struct ads7846_packet {
82 unsigned int count;
83 unsigned int count_skip;
84 unsigned int cmds;
85 unsigned int last_cmd_idx;
86 struct ads7846_buf_layout l[5];
87 struct ads7846_buf *rx;
88 struct ads7846_buf *tx;
89
90 struct ads7846_buf pwrdown_cmd;
91
92 bool ignore;
93 u16 x, y, z1, z2;
94};
95
96struct ads7846 {
97 struct input_dev *input;
98 char phys[32];
99 char name[32];
100
101 struct spi_device *spi;
102 struct regulator *reg;
103
104 u16 model;
105 u16 vref_mv;
106 u16 vref_delay_usecs;
107 u16 x_plate_ohms;
108 u16 pressure_max;
109
110 bool swap_xy;
111 bool use_internal;
112
113 struct ads7846_packet *packet;
114
115 struct spi_transfer xfer[18];
116 struct spi_message msg[5];
117 int msg_count;
118 wait_queue_head_t wait;
119
120 bool pendown;
121
122 int read_cnt;
123 int read_rep;
124 int last_read;
125
126 u16 debounce_max;
127 u16 debounce_tol;
128 u16 debounce_rep;
129
130 u16 penirq_recheck_delay_usecs;
131
132 struct touchscreen_properties core_prop;
133
134 struct mutex lock;
135 bool stopped; /* P: lock */
136 bool disabled; /* P: lock */
137 bool suspended; /* P: lock */
138
139 int (*filter)(void *data, int data_idx, int *val);
140 void *filter_data;
141 int (*get_pendown_state)(void);
142 int gpio_pendown;
143
144 void (*wait_for_sync)(void);
145};
146
147enum ads7846_filter {
148 ADS7846_FILTER_OK,
149 ADS7846_FILTER_REPEAT,
150 ADS7846_FILTER_IGNORE,
151};
152
153/* leave chip selected when we're done, for quicker re-select? */
154#if 0
155#define CS_CHANGE(xfer) ((xfer).cs_change = 1)
156#else
157#define CS_CHANGE(xfer) ((xfer).cs_change = 0)
158#endif
159
160/*--------------------------------------------------------------------------*/
161
162/* The ADS7846 has touchscreen and other sensors.
163 * Earlier ads784x chips are somewhat compatible.
164 */
165#define ADS_START (1 << 7)
166#define ADS_A2A1A0_d_y (1 << 4) /* differential */
167#define ADS_A2A1A0_d_z1 (3 << 4) /* differential */
168#define ADS_A2A1A0_d_z2 (4 << 4) /* differential */
169#define ADS_A2A1A0_d_x (5 << 4) /* differential */
170#define ADS_A2A1A0_temp0 (0 << 4) /* non-differential */
171#define ADS_A2A1A0_vbatt (2 << 4) /* non-differential */
172#define ADS_A2A1A0_vaux (6 << 4) /* non-differential */
173#define ADS_A2A1A0_temp1 (7 << 4) /* non-differential */
174#define ADS_8_BIT (1 << 3)
175#define ADS_12_BIT (0 << 3)
176#define ADS_SER (1 << 2) /* non-differential */
177#define ADS_DFR (0 << 2) /* differential */
178#define ADS_PD10_PDOWN (0 << 0) /* low power mode + penirq */
179#define ADS_PD10_ADC_ON (1 << 0) /* ADC on */
180#define ADS_PD10_REF_ON (2 << 0) /* vREF on + penirq */
181#define ADS_PD10_ALL_ON (3 << 0) /* ADC + vREF on */
182
183#define MAX_12BIT ((1<<12)-1)
184
185/* leave ADC powered up (disables penirq) between differential samples */
186#define READ_12BIT_DFR(x, adc, vref) (ADS_START | ADS_A2A1A0_d_ ## x \
187 | ADS_12_BIT | ADS_DFR | \
188 (adc ? ADS_PD10_ADC_ON : 0) | (vref ? ADS_PD10_REF_ON : 0))
189
190#define READ_Y(vref) (READ_12BIT_DFR(y, 1, vref))
191#define READ_Z1(vref) (READ_12BIT_DFR(z1, 1, vref))
192#define READ_Z2(vref) (READ_12BIT_DFR(z2, 1, vref))
193#define READ_X(vref) (READ_12BIT_DFR(x, 1, vref))
194#define PWRDOWN (READ_12BIT_DFR(y, 0, 0)) /* LAST */
195
196/* single-ended samples need to first power up reference voltage;
197 * we leave both ADC and VREF powered
198 */
199#define READ_12BIT_SER(x) (ADS_START | ADS_A2A1A0_ ## x \
200 | ADS_12_BIT | ADS_SER)
201
202#define REF_ON (READ_12BIT_DFR(x, 1, 1))
203#define REF_OFF (READ_12BIT_DFR(y, 0, 0))
204
205/* Order commands in the most optimal way to reduce Vref switching and
206 * settling time:
207 * Measure: X; Vref: X+, X-; IN: Y+
208 * Measure: Y; Vref: Y+, Y-; IN: X+
209 * Measure: Z1; Vref: Y+, X-; IN: X+
210 * Measure: Z2; Vref: Y+, X-; IN: Y-
211 */
212enum ads7846_cmds {
213 ADS7846_X,
214 ADS7846_Y,
215 ADS7846_Z1,
216 ADS7846_Z2,
217 ADS7846_PWDOWN,
218};
219
220static int get_pendown_state(struct ads7846 *ts)
221{
222 if (ts->get_pendown_state)
223 return ts->get_pendown_state();
224
225 return !gpio_get_value(ts->gpio_pendown);
226}
227
228static void ads7846_report_pen_up(struct ads7846 *ts)
229{
230 struct input_dev *input = ts->input;
231
232 input_report_key(input, BTN_TOUCH, 0);
233 input_report_abs(input, ABS_PRESSURE, 0);
234 input_sync(input);
235
236 ts->pendown = false;
237 dev_vdbg(&ts->spi->dev, "UP\n");
238}
239
240/* Must be called with ts->lock held */
241static void ads7846_stop(struct ads7846 *ts)
242{
243 if (!ts->disabled && !ts->suspended) {
244 /* Signal IRQ thread to stop polling and disable the handler. */
245 ts->stopped = true;
246 mb();
247 wake_up(&ts->wait);
248 disable_irq(ts->spi->irq);
249 }
250}
251
252/* Must be called with ts->lock held */
253static void ads7846_restart(struct ads7846 *ts)
254{
255 if (!ts->disabled && !ts->suspended) {
256 /* Check if pen was released since last stop */
257 if (ts->pendown && !get_pendown_state(ts))
258 ads7846_report_pen_up(ts);
259
260 /* Tell IRQ thread that it may poll the device. */
261 ts->stopped = false;
262 mb();
263 enable_irq(ts->spi->irq);
264 }
265}
266
267/* Must be called with ts->lock held */
268static void __ads7846_disable(struct ads7846 *ts)
269{
270 ads7846_stop(ts);
271 regulator_disable(ts->reg);
272
273 /*
274 * We know the chip's in low power mode since we always
275 * leave it that way after every request
276 */
277}
278
279/* Must be called with ts->lock held */
280static void __ads7846_enable(struct ads7846 *ts)
281{
282 int error;
283
284 error = regulator_enable(ts->reg);
285 if (error != 0)
286 dev_err(&ts->spi->dev, "Failed to enable supply: %d\n", error);
287
288 ads7846_restart(ts);
289}
290
291static void ads7846_disable(struct ads7846 *ts)
292{
293 mutex_lock(&ts->lock);
294
295 if (!ts->disabled) {
296
297 if (!ts->suspended)
298 __ads7846_disable(ts);
299
300 ts->disabled = true;
301 }
302
303 mutex_unlock(&ts->lock);
304}
305
306static void ads7846_enable(struct ads7846 *ts)
307{
308 mutex_lock(&ts->lock);
309
310 if (ts->disabled) {
311
312 ts->disabled = false;
313
314 if (!ts->suspended)
315 __ads7846_enable(ts);
316 }
317
318 mutex_unlock(&ts->lock);
319}
320
321/*--------------------------------------------------------------------------*/
322
323/*
324 * Non-touchscreen sensors only use single-ended conversions.
325 * The range is GND..vREF. The ads7843 and ads7835 must use external vREF;
326 * ads7846 lets that pin be unconnected, to use internal vREF.
327 */
328
329struct ser_req {
330 u8 ref_on;
331 u8 command;
332 u8 ref_off;
333 u16 scratch;
334 struct spi_message msg;
335 struct spi_transfer xfer[6];
336 /*
337 * DMA (thus cache coherency maintenance) requires the
338 * transfer buffers to live in their own cache lines.
339 */
340 __be16 sample ____cacheline_aligned;
341};
342
343struct ads7845_ser_req {
344 u8 command[3];
345 struct spi_message msg;
346 struct spi_transfer xfer[2];
347 /*
348 * DMA (thus cache coherency maintenance) requires the
349 * transfer buffers to live in their own cache lines.
350 */
351 u8 sample[3] ____cacheline_aligned;
352};
353
354static int ads7846_read12_ser(struct device *dev, unsigned command)
355{
356 struct spi_device *spi = to_spi_device(dev);
357 struct ads7846 *ts = dev_get_drvdata(dev);
358 struct ser_req *req;
359 int status;
360
361 req = kzalloc(sizeof *req, GFP_KERNEL);
362 if (!req)
363 return -ENOMEM;
364
365 spi_message_init(&req->msg);
366
367 /* maybe turn on internal vREF, and let it settle */
368 if (ts->use_internal) {
369 req->ref_on = REF_ON;
370 req->xfer[0].tx_buf = &req->ref_on;
371 req->xfer[0].len = 1;
372 spi_message_add_tail(&req->xfer[0], &req->msg);
373
374 req->xfer[1].rx_buf = &req->scratch;
375 req->xfer[1].len = 2;
376
377 /* for 1uF, settle for 800 usec; no cap, 100 usec. */
378 req->xfer[1].delay.value = ts->vref_delay_usecs;
379 req->xfer[1].delay.unit = SPI_DELAY_UNIT_USECS;
380 spi_message_add_tail(&req->xfer[1], &req->msg);
381
382 /* Enable reference voltage */
383 command |= ADS_PD10_REF_ON;
384 }
385
386 /* Enable ADC in every case */
387 command |= ADS_PD10_ADC_ON;
388
389 /* take sample */
390 req->command = (u8) command;
391 req->xfer[2].tx_buf = &req->command;
392 req->xfer[2].len = 1;
393 spi_message_add_tail(&req->xfer[2], &req->msg);
394
395 req->xfer[3].rx_buf = &req->sample;
396 req->xfer[3].len = 2;
397 spi_message_add_tail(&req->xfer[3], &req->msg);
398
399 /* REVISIT: take a few more samples, and compare ... */
400
401 /* converter in low power mode & enable PENIRQ */
402 req->ref_off = PWRDOWN;
403 req->xfer[4].tx_buf = &req->ref_off;
404 req->xfer[4].len = 1;
405 spi_message_add_tail(&req->xfer[4], &req->msg);
406
407 req->xfer[5].rx_buf = &req->scratch;
408 req->xfer[5].len = 2;
409 CS_CHANGE(req->xfer[5]);
410 spi_message_add_tail(&req->xfer[5], &req->msg);
411
412 mutex_lock(&ts->lock);
413 ads7846_stop(ts);
414 status = spi_sync(spi, &req->msg);
415 ads7846_restart(ts);
416 mutex_unlock(&ts->lock);
417
418 if (status == 0) {
419 /* on-wire is a must-ignore bit, a BE12 value, then padding */
420 status = be16_to_cpu(req->sample);
421 status = status >> 3;
422 status &= 0x0fff;
423 }
424
425 kfree(req);
426 return status;
427}
428
429static int ads7845_read12_ser(struct device *dev, unsigned command)
430{
431 struct spi_device *spi = to_spi_device(dev);
432 struct ads7846 *ts = dev_get_drvdata(dev);
433 struct ads7845_ser_req *req;
434 int status;
435
436 req = kzalloc(sizeof *req, GFP_KERNEL);
437 if (!req)
438 return -ENOMEM;
439
440 spi_message_init(&req->msg);
441
442 req->command[0] = (u8) command;
443 req->xfer[0].tx_buf = req->command;
444 req->xfer[0].rx_buf = req->sample;
445 req->xfer[0].len = 3;
446 spi_message_add_tail(&req->xfer[0], &req->msg);
447
448 mutex_lock(&ts->lock);
449 ads7846_stop(ts);
450 status = spi_sync(spi, &req->msg);
451 ads7846_restart(ts);
452 mutex_unlock(&ts->lock);
453
454 if (status == 0) {
455 /* BE12 value, then padding */
456 status = get_unaligned_be16(&req->sample[1]);
457 status = status >> 3;
458 status &= 0x0fff;
459 }
460
461 kfree(req);
462 return status;
463}
464
465#if IS_ENABLED(CONFIG_HWMON)
466
467#define SHOW(name, var, adjust) static ssize_t \
468name ## _show(struct device *dev, struct device_attribute *attr, char *buf) \
469{ \
470 struct ads7846 *ts = dev_get_drvdata(dev); \
471 ssize_t v = ads7846_read12_ser(&ts->spi->dev, \
472 READ_12BIT_SER(var)); \
473 if (v < 0) \
474 return v; \
475 return sprintf(buf, "%u\n", adjust(ts, v)); \
476} \
477static DEVICE_ATTR(name, S_IRUGO, name ## _show, NULL);
478
479
480/* Sysfs conventions report temperatures in millidegrees Celsius.
481 * ADS7846 could use the low-accuracy two-sample scheme, but can't do the high
482 * accuracy scheme without calibration data. For now we won't try either;
483 * userspace sees raw sensor values, and must scale/calibrate appropriately.
484 */
485static inline unsigned null_adjust(struct ads7846 *ts, ssize_t v)
486{
487 return v;
488}
489
490SHOW(temp0, temp0, null_adjust) /* temp1_input */
491SHOW(temp1, temp1, null_adjust) /* temp2_input */
492
493
494/* sysfs conventions report voltages in millivolts. We can convert voltages
495 * if we know vREF. userspace may need to scale vAUX to match the board's
496 * external resistors; we assume that vBATT only uses the internal ones.
497 */
498static inline unsigned vaux_adjust(struct ads7846 *ts, ssize_t v)
499{
500 unsigned retval = v;
501
502 /* external resistors may scale vAUX into 0..vREF */
503 retval *= ts->vref_mv;
504 retval = retval >> 12;
505
506 return retval;
507}
508
509static inline unsigned vbatt_adjust(struct ads7846 *ts, ssize_t v)
510{
511 unsigned retval = vaux_adjust(ts, v);
512
513 /* ads7846 has a resistor ladder to scale this signal down */
514 if (ts->model == 7846)
515 retval *= 4;
516
517 return retval;
518}
519
520SHOW(in0_input, vaux, vaux_adjust)
521SHOW(in1_input, vbatt, vbatt_adjust)
522
523static umode_t ads7846_is_visible(struct kobject *kobj, struct attribute *attr,
524 int index)
525{
526 struct device *dev = kobj_to_dev(kobj);
527 struct ads7846 *ts = dev_get_drvdata(dev);
528
529 if (ts->model == 7843 && index < 2) /* in0, in1 */
530 return 0;
531 if (ts->model == 7845 && index != 2) /* in0 */
532 return 0;
533
534 return attr->mode;
535}
536
537static struct attribute *ads7846_attributes[] = {
538 &dev_attr_temp0.attr, /* 0 */
539 &dev_attr_temp1.attr, /* 1 */
540 &dev_attr_in0_input.attr, /* 2 */
541 &dev_attr_in1_input.attr, /* 3 */
542 NULL,
543};
544
545static const struct attribute_group ads7846_attr_group = {
546 .attrs = ads7846_attributes,
547 .is_visible = ads7846_is_visible,
548};
549__ATTRIBUTE_GROUPS(ads7846_attr);
550
551static int ads784x_hwmon_register(struct spi_device *spi, struct ads7846 *ts)
552{
553 struct device *hwmon;
554
555 /* hwmon sensors need a reference voltage */
556 switch (ts->model) {
557 case 7846:
558 if (!ts->vref_mv) {
559 dev_dbg(&spi->dev, "assuming 2.5V internal vREF\n");
560 ts->vref_mv = 2500;
561 ts->use_internal = true;
562 }
563 break;
564 case 7845:
565 case 7843:
566 if (!ts->vref_mv) {
567 dev_warn(&spi->dev,
568 "external vREF for ADS%d not specified\n",
569 ts->model);
570 return 0;
571 }
572 break;
573 }
574
575 hwmon = devm_hwmon_device_register_with_groups(&spi->dev,
576 spi->modalias, ts,
577 ads7846_attr_groups);
578
579 return PTR_ERR_OR_ZERO(hwmon);
580}
581
582#else
583static inline int ads784x_hwmon_register(struct spi_device *spi,
584 struct ads7846 *ts)
585{
586 return 0;
587}
588#endif
589
590static ssize_t ads7846_pen_down_show(struct device *dev,
591 struct device_attribute *attr, char *buf)
592{
593 struct ads7846 *ts = dev_get_drvdata(dev);
594
595 return sprintf(buf, "%u\n", ts->pendown);
596}
597
598static DEVICE_ATTR(pen_down, S_IRUGO, ads7846_pen_down_show, NULL);
599
600static ssize_t ads7846_disable_show(struct device *dev,
601 struct device_attribute *attr, char *buf)
602{
603 struct ads7846 *ts = dev_get_drvdata(dev);
604
605 return sprintf(buf, "%u\n", ts->disabled);
606}
607
608static ssize_t ads7846_disable_store(struct device *dev,
609 struct device_attribute *attr,
610 const char *buf, size_t count)
611{
612 struct ads7846 *ts = dev_get_drvdata(dev);
613 unsigned int i;
614 int err;
615
616 err = kstrtouint(buf, 10, &i);
617 if (err)
618 return err;
619
620 if (i)
621 ads7846_disable(ts);
622 else
623 ads7846_enable(ts);
624
625 return count;
626}
627
628static DEVICE_ATTR(disable, 0664, ads7846_disable_show, ads7846_disable_store);
629
630static struct attribute *ads784x_attributes[] = {
631 &dev_attr_pen_down.attr,
632 &dev_attr_disable.attr,
633 NULL,
634};
635
636static const struct attribute_group ads784x_attr_group = {
637 .attrs = ads784x_attributes,
638};
639
640/*--------------------------------------------------------------------------*/
641
642static void null_wait_for_sync(void)
643{
644}
645
646static int ads7846_debounce_filter(void *ads, int data_idx, int *val)
647{
648 struct ads7846 *ts = ads;
649
650 if (!ts->read_cnt || (abs(ts->last_read - *val) > ts->debounce_tol)) {
651 /* Start over collecting consistent readings. */
652 ts->read_rep = 0;
653 /*
654 * Repeat it, if this was the first read or the read
655 * wasn't consistent enough.
656 */
657 if (ts->read_cnt < ts->debounce_max) {
658 ts->last_read = *val;
659 ts->read_cnt++;
660 return ADS7846_FILTER_REPEAT;
661 } else {
662 /*
663 * Maximum number of debouncing reached and still
664 * not enough number of consistent readings. Abort
665 * the whole sample, repeat it in the next sampling
666 * period.
667 */
668 ts->read_cnt = 0;
669 return ADS7846_FILTER_IGNORE;
670 }
671 } else {
672 if (++ts->read_rep > ts->debounce_rep) {
673 /*
674 * Got a good reading for this coordinate,
675 * go for the next one.
676 */
677 ts->read_cnt = 0;
678 ts->read_rep = 0;
679 return ADS7846_FILTER_OK;
680 } else {
681 /* Read more values that are consistent. */
682 ts->read_cnt++;
683 return ADS7846_FILTER_REPEAT;
684 }
685 }
686}
687
688static int ads7846_no_filter(void *ads, int data_idx, int *val)
689{
690 return ADS7846_FILTER_OK;
691}
692
693static int ads7846_get_value(struct ads7846_buf *buf)
694{
695 int value;
696
697 value = be16_to_cpup(&buf->data);
698
699 /* enforce ADC output is 12 bits width */
700 return (value >> 3) & 0xfff;
701}
702
703static void ads7846_set_cmd_val(struct ads7846 *ts, enum ads7846_cmds cmd_idx,
704 u16 val)
705{
706 struct ads7846_packet *packet = ts->packet;
707
708 switch (cmd_idx) {
709 case ADS7846_Y:
710 packet->y = val;
711 break;
712 case ADS7846_X:
713 packet->x = val;
714 break;
715 case ADS7846_Z1:
716 packet->z1 = val;
717 break;
718 case ADS7846_Z2:
719 packet->z2 = val;
720 break;
721 default:
722 WARN_ON_ONCE(1);
723 }
724}
725
726static u8 ads7846_get_cmd(enum ads7846_cmds cmd_idx, int vref)
727{
728 switch (cmd_idx) {
729 case ADS7846_Y:
730 return READ_Y(vref);
731 case ADS7846_X:
732 return READ_X(vref);
733
734 /* 7846 specific commands */
735 case ADS7846_Z1:
736 return READ_Z1(vref);
737 case ADS7846_Z2:
738 return READ_Z2(vref);
739 case ADS7846_PWDOWN:
740 return PWRDOWN;
741 default:
742 WARN_ON_ONCE(1);
743 }
744
745 return 0;
746}
747
748static bool ads7846_cmd_need_settle(enum ads7846_cmds cmd_idx)
749{
750 switch (cmd_idx) {
751 case ADS7846_X:
752 case ADS7846_Y:
753 case ADS7846_Z1:
754 case ADS7846_Z2:
755 return true;
756 case ADS7846_PWDOWN:
757 return false;
758 default:
759 WARN_ON_ONCE(1);
760 }
761
762 return false;
763}
764
765static int ads7846_filter(struct ads7846 *ts)
766{
767 struct ads7846_packet *packet = ts->packet;
768 int action;
769 int val;
770 unsigned int cmd_idx, b;
771
772 packet->ignore = false;
773 for (cmd_idx = packet->last_cmd_idx; cmd_idx < packet->cmds - 1; cmd_idx++) {
774 struct ads7846_buf_layout *l = &packet->l[cmd_idx];
775
776 packet->last_cmd_idx = cmd_idx;
777
778 for (b = l->skip; b < l->count; b++) {
779 val = ads7846_get_value(&packet->rx[l->offset + b]);
780
781 action = ts->filter(ts->filter_data, cmd_idx, &val);
782 if (action == ADS7846_FILTER_REPEAT) {
783 if (b == l->count - 1)
784 return -EAGAIN;
785 } else if (action == ADS7846_FILTER_OK) {
786 ads7846_set_cmd_val(ts, cmd_idx, val);
787 break;
788 } else {
789 packet->ignore = true;
790 return 0;
791 }
792 }
793 }
794
795 return 0;
796}
797
798static void ads7846_read_state(struct ads7846 *ts)
799{
800 struct ads7846_packet *packet = ts->packet;
801 struct spi_message *m;
802 int msg_idx = 0;
803 int error;
804
805 packet->last_cmd_idx = 0;
806
807 while (true) {
808 ts->wait_for_sync();
809
810 m = &ts->msg[msg_idx];
811 error = spi_sync(ts->spi, m);
812 if (error) {
813 dev_err(&ts->spi->dev, "spi_sync --> %d\n", error);
814 packet->ignore = true;
815 return;
816 }
817
818 error = ads7846_filter(ts);
819 if (error)
820 continue;
821
822 return;
823 }
824}
825
826static void ads7846_report_state(struct ads7846 *ts)
827{
828 struct ads7846_packet *packet = ts->packet;
829 unsigned int Rt;
830 u16 x, y, z1, z2;
831
832 x = packet->x;
833 y = packet->y;
834 if (ts->model == 7845) {
835 z1 = 0;
836 z2 = 0;
837 } else {
838 z1 = packet->z1;
839 z2 = packet->z2;
840 }
841
842 /* range filtering */
843 if (x == MAX_12BIT)
844 x = 0;
845
846 if (ts->model == 7843) {
847 Rt = ts->pressure_max / 2;
848 } else if (ts->model == 7845) {
849 if (get_pendown_state(ts))
850 Rt = ts->pressure_max / 2;
851 else
852 Rt = 0;
853 dev_vdbg(&ts->spi->dev, "x/y: %d/%d, PD %d\n", x, y, Rt);
854 } else if (likely(x && z1)) {
855 /* compute touch pressure resistance using equation #2 */
856 Rt = z2;
857 Rt -= z1;
858 Rt *= ts->x_plate_ohms;
859 Rt = DIV_ROUND_CLOSEST(Rt, 16);
860 Rt *= x;
861 Rt /= z1;
862 Rt = DIV_ROUND_CLOSEST(Rt, 256);
863 } else {
864 Rt = 0;
865 }
866
867 /*
868 * Sample found inconsistent by debouncing or pressure is beyond
869 * the maximum. Don't report it to user space, repeat at least
870 * once more the measurement
871 */
872 if (packet->ignore || Rt > ts->pressure_max) {
873 dev_vdbg(&ts->spi->dev, "ignored %d pressure %d\n",
874 packet->ignore, Rt);
875 return;
876 }
877
878 /*
879 * Maybe check the pendown state before reporting. This discards
880 * false readings when the pen is lifted.
881 */
882 if (ts->penirq_recheck_delay_usecs) {
883 udelay(ts->penirq_recheck_delay_usecs);
884 if (!get_pendown_state(ts))
885 Rt = 0;
886 }
887
888 /*
889 * NOTE: We can't rely on the pressure to determine the pen down
890 * state, even this controller has a pressure sensor. The pressure
891 * value can fluctuate for quite a while after lifting the pen and
892 * in some cases may not even settle at the expected value.
893 *
894 * The only safe way to check for the pen up condition is in the
895 * timer by reading the pen signal state (it's a GPIO _and_ IRQ).
896 */
897 if (Rt) {
898 struct input_dev *input = ts->input;
899
900 if (!ts->pendown) {
901 input_report_key(input, BTN_TOUCH, 1);
902 ts->pendown = true;
903 dev_vdbg(&ts->spi->dev, "DOWN\n");
904 }
905
906 touchscreen_report_pos(input, &ts->core_prop, x, y, false);
907 input_report_abs(input, ABS_PRESSURE, ts->pressure_max - Rt);
908
909 input_sync(input);
910 dev_vdbg(&ts->spi->dev, "%4d/%4d/%4d\n", x, y, Rt);
911 }
912}
913
914static irqreturn_t ads7846_hard_irq(int irq, void *handle)
915{
916 struct ads7846 *ts = handle;
917
918 return get_pendown_state(ts) ? IRQ_WAKE_THREAD : IRQ_HANDLED;
919}
920
921
922static irqreturn_t ads7846_irq(int irq, void *handle)
923{
924 struct ads7846 *ts = handle;
925
926 /* Start with a small delay before checking pendown state */
927 msleep(TS_POLL_DELAY);
928
929 while (!ts->stopped && get_pendown_state(ts)) {
930
931 /* pen is down, continue with the measurement */
932 ads7846_read_state(ts);
933
934 if (!ts->stopped)
935 ads7846_report_state(ts);
936
937 wait_event_timeout(ts->wait, ts->stopped,
938 msecs_to_jiffies(TS_POLL_PERIOD));
939 }
940
941 if (ts->pendown && !ts->stopped)
942 ads7846_report_pen_up(ts);
943
944 return IRQ_HANDLED;
945}
946
947static int __maybe_unused ads7846_suspend(struct device *dev)
948{
949 struct ads7846 *ts = dev_get_drvdata(dev);
950
951 mutex_lock(&ts->lock);
952
953 if (!ts->suspended) {
954
955 if (!ts->disabled)
956 __ads7846_disable(ts);
957
958 if (device_may_wakeup(&ts->spi->dev))
959 enable_irq_wake(ts->spi->irq);
960
961 ts->suspended = true;
962 }
963
964 mutex_unlock(&ts->lock);
965
966 return 0;
967}
968
969static int __maybe_unused ads7846_resume(struct device *dev)
970{
971 struct ads7846 *ts = dev_get_drvdata(dev);
972
973 mutex_lock(&ts->lock);
974
975 if (ts->suspended) {
976
977 ts->suspended = false;
978
979 if (device_may_wakeup(&ts->spi->dev))
980 disable_irq_wake(ts->spi->irq);
981
982 if (!ts->disabled)
983 __ads7846_enable(ts);
984 }
985
986 mutex_unlock(&ts->lock);
987
988 return 0;
989}
990
991static SIMPLE_DEV_PM_OPS(ads7846_pm, ads7846_suspend, ads7846_resume);
992
993static int ads7846_setup_pendown(struct spi_device *spi,
994 struct ads7846 *ts,
995 const struct ads7846_platform_data *pdata)
996{
997 int err;
998
999 /*
1000 * REVISIT when the irq can be triggered active-low, or if for some
1001 * reason the touchscreen isn't hooked up, we don't need to access
1002 * the pendown state.
1003 */
1004
1005 if (pdata->get_pendown_state) {
1006 ts->get_pendown_state = pdata->get_pendown_state;
1007 } else if (gpio_is_valid(pdata->gpio_pendown)) {
1008
1009 err = devm_gpio_request_one(&spi->dev, pdata->gpio_pendown,
1010 GPIOF_IN, "ads7846_pendown");
1011 if (err) {
1012 dev_err(&spi->dev,
1013 "failed to request/setup pendown GPIO%d: %d\n",
1014 pdata->gpio_pendown, err);
1015 return err;
1016 }
1017
1018 ts->gpio_pendown = pdata->gpio_pendown;
1019
1020 if (pdata->gpio_pendown_debounce)
1021 gpio_set_debounce(pdata->gpio_pendown,
1022 pdata->gpio_pendown_debounce);
1023 } else {
1024 dev_err(&spi->dev, "no get_pendown_state nor gpio_pendown?\n");
1025 return -EINVAL;
1026 }
1027
1028 return 0;
1029}
1030
1031/*
1032 * Set up the transfers to read touchscreen state; this assumes we
1033 * use formula #2 for pressure, not #3.
1034 */
1035static int ads7846_setup_spi_msg(struct ads7846 *ts,
1036 const struct ads7846_platform_data *pdata)
1037{
1038 struct spi_message *m = &ts->msg[0];
1039 struct spi_transfer *x = ts->xfer;
1040 struct ads7846_packet *packet = ts->packet;
1041 int vref = pdata->keep_vref_on;
1042 unsigned int count, offset = 0;
1043 unsigned int cmd_idx, b;
1044 unsigned long time;
1045 size_t size = 0;
1046
1047 /* time per bit */
1048 time = NSEC_PER_SEC / ts->spi->max_speed_hz;
1049
1050 count = pdata->settle_delay_usecs * NSEC_PER_USEC / time;
1051 packet->count_skip = DIV_ROUND_UP(count, 24);
1052
1053 if (ts->debounce_max && ts->debounce_rep)
1054 /* ads7846_debounce_filter() is making ts->debounce_rep + 2
1055 * reads. So we need to get all samples for normal case. */
1056 packet->count = ts->debounce_rep + 2;
1057 else
1058 packet->count = 1;
1059
1060 if (ts->model == 7846)
1061 packet->cmds = 5; /* x, y, z1, z2, pwdown */
1062 else
1063 packet->cmds = 3; /* x, y, pwdown */
1064
1065 for (cmd_idx = 0; cmd_idx < packet->cmds; cmd_idx++) {
1066 struct ads7846_buf_layout *l = &packet->l[cmd_idx];
1067 unsigned int max_count;
1068
1069 if (ads7846_cmd_need_settle(cmd_idx))
1070 max_count = packet->count + packet->count_skip;
1071 else
1072 max_count = packet->count;
1073
1074 l->offset = offset;
1075 offset += max_count;
1076 l->count = max_count;
1077 l->skip = packet->count_skip;
1078 size += sizeof(*packet->tx) * max_count;
1079 }
1080
1081 packet->tx = devm_kzalloc(&ts->spi->dev, size, GFP_KERNEL);
1082 if (!packet->tx)
1083 return -ENOMEM;
1084
1085 packet->rx = devm_kzalloc(&ts->spi->dev, size, GFP_KERNEL);
1086 if (!packet->rx)
1087 return -ENOMEM;
1088
1089 if (ts->model == 7873) {
1090 /*
1091 * The AD7873 is almost identical to the ADS7846
1092 * keep VREF off during differential/ratiometric
1093 * conversion modes.
1094 */
1095 ts->model = 7846;
1096 vref = 0;
1097 }
1098
1099 ts->msg_count = 1;
1100 spi_message_init(m);
1101 m->context = ts;
1102
1103 for (cmd_idx = 0; cmd_idx < packet->cmds; cmd_idx++) {
1104 struct ads7846_buf_layout *l = &packet->l[cmd_idx];
1105 u8 cmd = ads7846_get_cmd(cmd_idx, vref);
1106
1107 for (b = 0; b < l->count; b++)
1108 packet->tx[l->offset + b].cmd = cmd;
1109 }
1110
1111 x->tx_buf = packet->tx;
1112 x->rx_buf = packet->rx;
1113 x->len = size;
1114 spi_message_add_tail(x, m);
1115
1116 return 0;
1117}
1118
1119#ifdef CONFIG_OF
1120static const struct of_device_id ads7846_dt_ids[] = {
1121 { .compatible = "ti,tsc2046", .data = (void *) 7846 },
1122 { .compatible = "ti,ads7843", .data = (void *) 7843 },
1123 { .compatible = "ti,ads7845", .data = (void *) 7845 },
1124 { .compatible = "ti,ads7846", .data = (void *) 7846 },
1125 { .compatible = "ti,ads7873", .data = (void *) 7873 },
1126 { }
1127};
1128MODULE_DEVICE_TABLE(of, ads7846_dt_ids);
1129
1130static const struct ads7846_platform_data *ads7846_probe_dt(struct device *dev)
1131{
1132 struct ads7846_platform_data *pdata;
1133 struct device_node *node = dev->of_node;
1134 const struct of_device_id *match;
1135 u32 value;
1136
1137 if (!node) {
1138 dev_err(dev, "Device does not have associated DT data\n");
1139 return ERR_PTR(-EINVAL);
1140 }
1141
1142 match = of_match_device(ads7846_dt_ids, dev);
1143 if (!match) {
1144 dev_err(dev, "Unknown device model\n");
1145 return ERR_PTR(-EINVAL);
1146 }
1147
1148 pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
1149 if (!pdata)
1150 return ERR_PTR(-ENOMEM);
1151
1152 pdata->model = (unsigned long)match->data;
1153
1154 of_property_read_u16(node, "ti,vref-delay-usecs",
1155 &pdata->vref_delay_usecs);
1156 of_property_read_u16(node, "ti,vref-mv", &pdata->vref_mv);
1157 pdata->keep_vref_on = of_property_read_bool(node, "ti,keep-vref-on");
1158
1159 pdata->swap_xy = of_property_read_bool(node, "ti,swap-xy");
1160
1161 of_property_read_u16(node, "ti,settle-delay-usec",
1162 &pdata->settle_delay_usecs);
1163 of_property_read_u16(node, "ti,penirq-recheck-delay-usecs",
1164 &pdata->penirq_recheck_delay_usecs);
1165
1166 of_property_read_u16(node, "ti,x-plate-ohms", &pdata->x_plate_ohms);
1167 of_property_read_u16(node, "ti,y-plate-ohms", &pdata->y_plate_ohms);
1168
1169 of_property_read_u16(node, "ti,x-min", &pdata->x_min);
1170 of_property_read_u16(node, "ti,y-min", &pdata->y_min);
1171 of_property_read_u16(node, "ti,x-max", &pdata->x_max);
1172 of_property_read_u16(node, "ti,y-max", &pdata->y_max);
1173
1174 /*
1175 * touchscreen-max-pressure gets parsed during
1176 * touchscreen_parse_properties()
1177 */
1178 of_property_read_u16(node, "ti,pressure-min", &pdata->pressure_min);
1179 if (!of_property_read_u32(node, "touchscreen-min-pressure", &value))
1180 pdata->pressure_min = (u16) value;
1181 of_property_read_u16(node, "ti,pressure-max", &pdata->pressure_max);
1182
1183 of_property_read_u16(node, "ti,debounce-max", &pdata->debounce_max);
1184 if (!of_property_read_u32(node, "touchscreen-average-samples", &value))
1185 pdata->debounce_max = (u16) value;
1186 of_property_read_u16(node, "ti,debounce-tol", &pdata->debounce_tol);
1187 of_property_read_u16(node, "ti,debounce-rep", &pdata->debounce_rep);
1188
1189 of_property_read_u32(node, "ti,pendown-gpio-debounce",
1190 &pdata->gpio_pendown_debounce);
1191
1192 pdata->wakeup = of_property_read_bool(node, "wakeup-source") ||
1193 of_property_read_bool(node, "linux,wakeup");
1194
1195 pdata->gpio_pendown = of_get_named_gpio(dev->of_node, "pendown-gpio", 0);
1196
1197 return pdata;
1198}
1199#else
1200static const struct ads7846_platform_data *ads7846_probe_dt(struct device *dev)
1201{
1202 dev_err(dev, "no platform data defined\n");
1203 return ERR_PTR(-EINVAL);
1204}
1205#endif
1206
1207static void ads7846_regulator_disable(void *regulator)
1208{
1209 regulator_disable(regulator);
1210}
1211
1212static int ads7846_probe(struct spi_device *spi)
1213{
1214 const struct ads7846_platform_data *pdata;
1215 struct ads7846 *ts;
1216 struct device *dev = &spi->dev;
1217 struct ads7846_packet *packet;
1218 struct input_dev *input_dev;
1219 unsigned long irq_flags;
1220 int err;
1221
1222 if (!spi->irq) {
1223 dev_dbg(dev, "no IRQ?\n");
1224 return -EINVAL;
1225 }
1226
1227 /* don't exceed max specified sample rate */
1228 if (spi->max_speed_hz > (125000 * SAMPLE_BITS)) {
1229 dev_err(dev, "f(sample) %d KHz?\n",
1230 (spi->max_speed_hz/SAMPLE_BITS)/1000);
1231 return -EINVAL;
1232 }
1233
1234 /*
1235 * We'd set TX word size 8 bits and RX word size to 13 bits ... except
1236 * that even if the hardware can do that, the SPI controller driver
1237 * may not. So we stick to very-portable 8 bit words, both RX and TX.
1238 */
1239 spi->bits_per_word = 8;
1240 spi->mode &= ~SPI_MODE_X_MASK;
1241 spi->mode |= SPI_MODE_0;
1242 err = spi_setup(spi);
1243 if (err < 0)
1244 return err;
1245
1246 ts = devm_kzalloc(dev, sizeof(struct ads7846), GFP_KERNEL);
1247 if (!ts)
1248 return -ENOMEM;
1249
1250 packet = devm_kzalloc(dev, sizeof(struct ads7846_packet), GFP_KERNEL);
1251 if (!packet)
1252 return -ENOMEM;
1253
1254 input_dev = devm_input_allocate_device(dev);
1255 if (!input_dev)
1256 return -ENOMEM;
1257
1258 spi_set_drvdata(spi, ts);
1259
1260 ts->packet = packet;
1261 ts->spi = spi;
1262 ts->input = input_dev;
1263
1264 mutex_init(&ts->lock);
1265 init_waitqueue_head(&ts->wait);
1266
1267 pdata = dev_get_platdata(dev);
1268 if (!pdata) {
1269 pdata = ads7846_probe_dt(dev);
1270 if (IS_ERR(pdata))
1271 return PTR_ERR(pdata);
1272 }
1273
1274 ts->model = pdata->model ? : 7846;
1275 ts->vref_delay_usecs = pdata->vref_delay_usecs ? : 100;
1276 ts->x_plate_ohms = pdata->x_plate_ohms ? : 400;
1277 ts->vref_mv = pdata->vref_mv;
1278
1279 if (pdata->debounce_max) {
1280 ts->debounce_max = pdata->debounce_max;
1281 if (ts->debounce_max < 2)
1282 ts->debounce_max = 2;
1283 ts->debounce_tol = pdata->debounce_tol;
1284 ts->debounce_rep = pdata->debounce_rep;
1285 ts->filter = ads7846_debounce_filter;
1286 ts->filter_data = ts;
1287 } else {
1288 ts->filter = ads7846_no_filter;
1289 }
1290
1291 err = ads7846_setup_pendown(spi, ts, pdata);
1292 if (err)
1293 return err;
1294
1295 if (pdata->penirq_recheck_delay_usecs)
1296 ts->penirq_recheck_delay_usecs =
1297 pdata->penirq_recheck_delay_usecs;
1298
1299 ts->wait_for_sync = pdata->wait_for_sync ? : null_wait_for_sync;
1300
1301 snprintf(ts->phys, sizeof(ts->phys), "%s/input0", dev_name(dev));
1302 snprintf(ts->name, sizeof(ts->name), "ADS%d Touchscreen", ts->model);
1303
1304 input_dev->name = ts->name;
1305 input_dev->phys = ts->phys;
1306
1307 input_dev->id.bustype = BUS_SPI;
1308 input_dev->id.product = pdata->model;
1309
1310 input_set_capability(input_dev, EV_KEY, BTN_TOUCH);
1311 input_set_abs_params(input_dev, ABS_X,
1312 pdata->x_min ? : 0,
1313 pdata->x_max ? : MAX_12BIT,
1314 0, 0);
1315 input_set_abs_params(input_dev, ABS_Y,
1316 pdata->y_min ? : 0,
1317 pdata->y_max ? : MAX_12BIT,
1318 0, 0);
1319 input_set_abs_params(input_dev, ABS_PRESSURE,
1320 pdata->pressure_min, pdata->pressure_max, 0, 0);
1321
1322 /*
1323 * Parse common framework properties. Must be done here to ensure the
1324 * correct behaviour in case of using the legacy vendor bindings. The
1325 * general binding value overrides the vendor specific one.
1326 */
1327 touchscreen_parse_properties(ts->input, false, &ts->core_prop);
1328 ts->pressure_max = input_abs_get_max(input_dev, ABS_PRESSURE) ? : ~0;
1329
1330 /*
1331 * Check if legacy ti,swap-xy binding is used instead of
1332 * touchscreen-swapped-x-y
1333 */
1334 if (!ts->core_prop.swap_x_y && pdata->swap_xy) {
1335 swap(input_dev->absinfo[ABS_X], input_dev->absinfo[ABS_Y]);
1336 ts->core_prop.swap_x_y = true;
1337 }
1338
1339 ads7846_setup_spi_msg(ts, pdata);
1340
1341 ts->reg = devm_regulator_get(dev, "vcc");
1342 if (IS_ERR(ts->reg)) {
1343 err = PTR_ERR(ts->reg);
1344 dev_err(dev, "unable to get regulator: %d\n", err);
1345 return err;
1346 }
1347
1348 err = regulator_enable(ts->reg);
1349 if (err) {
1350 dev_err(dev, "unable to enable regulator: %d\n", err);
1351 return err;
1352 }
1353
1354 err = devm_add_action_or_reset(dev, ads7846_regulator_disable, ts->reg);
1355 if (err)
1356 return err;
1357
1358 irq_flags = pdata->irq_flags ? : IRQF_TRIGGER_FALLING;
1359 irq_flags |= IRQF_ONESHOT;
1360
1361 err = devm_request_threaded_irq(dev, spi->irq,
1362 ads7846_hard_irq, ads7846_irq,
1363 irq_flags, dev->driver->name, ts);
1364 if (err && err != -EPROBE_DEFER && !pdata->irq_flags) {
1365 dev_info(dev,
1366 "trying pin change workaround on irq %d\n", spi->irq);
1367 irq_flags |= IRQF_TRIGGER_RISING;
1368 err = devm_request_threaded_irq(dev, spi->irq,
1369 ads7846_hard_irq, ads7846_irq,
1370 irq_flags, dev->driver->name,
1371 ts);
1372 }
1373
1374 if (err) {
1375 dev_dbg(dev, "irq %d busy?\n", spi->irq);
1376 return err;
1377 }
1378
1379 err = ads784x_hwmon_register(spi, ts);
1380 if (err)
1381 return err;
1382
1383 dev_info(dev, "touchscreen, irq %d\n", spi->irq);
1384
1385 /*
1386 * Take a first sample, leaving nPENIRQ active and vREF off; avoid
1387 * the touchscreen, in case it's not connected.
1388 */
1389 if (ts->model == 7845)
1390 ads7845_read12_ser(dev, PWRDOWN);
1391 else
1392 (void) ads7846_read12_ser(dev, READ_12BIT_SER(vaux));
1393
1394 err = devm_device_add_group(dev, &ads784x_attr_group);
1395 if (err)
1396 return err;
1397
1398 err = input_register_device(input_dev);
1399 if (err)
1400 return err;
1401
1402 device_init_wakeup(dev, pdata->wakeup);
1403
1404 /*
1405 * If device does not carry platform data we must have allocated it
1406 * when parsing DT data.
1407 */
1408 if (!dev_get_platdata(dev))
1409 devm_kfree(dev, (void *)pdata);
1410
1411 return 0;
1412}
1413
1414static void ads7846_remove(struct spi_device *spi)
1415{
1416 struct ads7846 *ts = spi_get_drvdata(spi);
1417
1418 ads7846_stop(ts);
1419}
1420
1421static struct spi_driver ads7846_driver = {
1422 .driver = {
1423 .name = "ads7846",
1424 .pm = &ads7846_pm,
1425 .of_match_table = of_match_ptr(ads7846_dt_ids),
1426 },
1427 .probe = ads7846_probe,
1428 .remove = ads7846_remove,
1429};
1430
1431module_spi_driver(ads7846_driver);
1432
1433MODULE_DESCRIPTION("ADS7846 TouchScreen Driver");
1434MODULE_LICENSE("GPL");
1435MODULE_ALIAS("spi:ads7846");